Tumor-specific glycolipid antigens will be isolated and characterized. The purified glycolipids will be used to isolate human antibody-producing cells of the desired specificity. The cells will be "immortalized" by EB virus transformation or hybridomas will be prepared from them in order to obtain monoclonal antibodies. Oligosaccharides will be isolated from natural sources. Oligosaccharides will be coupled to macromolecules in order to make antibodies specific for certain sugar sequences. The antibodies will be used in radioimmune assays for the occurrence of these sugar sequences in the glycolipids and glycoproteins of carbohydrates of cell surfaces in development and regulation or as tumor-specific antigens. Carbohydrates on cell membranes that are receptors for toxins, hormones, and antibodies will be isolated and characterized.